Bug 6586

Hi! I have an iBook G4 with a radeon card. I have gotten the external monitor to
work using MergedFB, which gives me a Xinerama display spanning my internal LCD
and my external monitor.

I would like to get two separate desktops instead of one. Unfortunately, if I
turn off MergedFB (either by commenting it out, or setting it to "False"), when
I start X, my external monitor goes dark, and only my LCD displays the root window.

Here's what I'm trying wrt. the attached xorg.conf file:

Scenario 1:
- Set
  Option "MergedFB" "True"
- Run X -layout Plain
Effect: It works great, but /with/ Xinerama

Scenario 2:
- Set
  Option "MergedFB" "False"
- Run X -layout Separate
Effect: External monitor goes dark, and doesn't turn on

http://ozlabs.org/~jk/docs/mergefb/ mentions a radeontool hack that will let you
turn on the external DVI by setting register FP_GEN_CNTL. I would have tried the
hacked-up radeontool, but my card differs from the one documented there, and I'm
reluctant to play around with the card's registers.

How can I get two separate desktops with the "radeon" driver ?